Device for feeding pressure fluid from a stationary pressure source into a rotating member

ABSTRACT

A non-rotatable ring is arranged within an annular recess in a circumferential portion of a rotatable cylindrical member. The facing end walls at each end of the recessed portion of the cylinder and of the ring are provided with annular slots defining pressure transmitting regions and pressure throttling zones. A pressure fluid feeding conduit is arranged within the nonrotatable ring and opens into one of the pressure transmitting regions. The opposite pressure transmitting regions are interconnected and cooperate with the throttling zones in such a manner as to cause axial vibrations of the non-rotational ring resulting in a self-adjusting pressure balance in both interspaces when the pressure fluid is applied into the feeding conduit.

United States Patent Hiestand Nov. 13, 1973 [54] DEVICE FOR FEEDINGPRESSURE FLUID 2,752,197 6/1956 Marco 285/190 X OM A STATIONARY PRESSURESOURCE 2,812,186 11/1957 Carlsen et al 279/4 1 3,130,645 4/1964 'Hohwart92/106 X INTO A ROTATING MEMBER 3,417,672 12/1968 Sampson 92/106 [75]Inventor: Karl Hiestand, Pfullendorf, 3,545,342 12/1970 l-liestand92/106 Germany Prima Examinerlrwin C. Cohen 73 A 1 SMW-S 111 W 1 sslgneezf z xz zssf Attorney-Ernest F. Marmorek 7 Friedrichshafen, Germany 221Filed: Feb. 10, 1972 [57] ABSTRACT A non-rotatable ring is arrangedwithin an annular re- 1 [211 App! 225093 cess in 'a circumferentialportion of a rotatable cylindrical member. The facing end walls at eachend of [30] Foreign Application Priority Data the recessed portion ofthe cylinder and of the ring are Mar. 10, 1971 Germany. P 21 11 355.3Provided with annular defining Pressre transmit ting regions andpressure throttling zones. A pressure 52 US. (:1 279/4, 91/462, 92/106fluid feeding conduit is arranged within the [51] Int. Cl. B23b 31/30,Fl5b 13/04 rotatable ring and Opens into one of the Pressure 58 Field ofSearch 92/106- 91/462; transmitting regime The Pressure transmit- 279/4.285/19O 136 ting regions are interconnected and cooperate with thethrottling zones in such a manner as to cause axial [56] ReferencesCited vibrations of the non-rotational ring resulting in a self- UNITEDSTATES PATENTS adjusting pressure balance in both interspaces when thepressure fluid is applied into the feeding conduit. 2,230,881 2/1941Browne 285/190 X 2,577,656 12/1951 Hohwart et a1. 279/4 13 Claims, 4Drawing Figures lllll PATENTEB NOV 13 1975 SHEET 16F 3 PATENTEDHUV13 ms3.771. 803

sum '3 er 3 DEVICE FOR FEEDING PRESSURE FLUID FROM A STATIONARY PRESSURESOURCE INTO A ROTATING MEMBER REFERENCE TO RELATED APPLICATIONSReference is had to U.S. Pat. No. 3,545,342, issued Dec. 8, 1970 andentitled Pressure Fluid Supply Apparatus," and to U.S. Pat. No.3,635,481, issued Jan. 18, 1972 and entitled Chuck for Machine Tools.

BACKGROUND OF THE INVENTION This invention relates generally to devicescontrolled by a pressure fluid and more particularly it relates to adevice for delivering a pressure fluid from a stationary pressure supplyunit into a rotating member such as for example into a piston-cylinderhydraulic pressure device disposed within a rotating chuck body forhydraulically controlling the radially movable clamping jaws of thischuck body, or to a hydraulically controlledcoupling member.

In feeding a pressure fluid from a stationary feeding conduit into acylindrical member rotating about an axis, such as a rotatable chuck orrotatable coupling for example, there have been encountered manydifficulties due to the fact that the sealing means between thestationary member and the rotating member are subject to increasedfriction when the pressure fluid is supplied. As a consequence, thesealing means are susceptible to increased wear or damage and a flawlessdelivery of the pressure fluid no longer takes place.

To prevent the abrasion of a sealing collar resting on the rotatingcylinder of a pneumatically operated chuck, it has been suggested toprovide a stationary coupling ring coupled to pressure air conduits andan axially displaceable sealing ring disposed in a groove between thestationary coupling ring and the face surface of the rotating chuckbody; pressure air supplied from the feeding conduit urges the sealingring against the face surface of the rotating cylinder and protects theopposite surfaces of the rotatable and non-rotatable members againstabrasion.

The disadvantage of such prior art solution is in that the machining ofguiding and supporting means on the stationary ring is very expensive.In addition, the stationary ring which is connected with'pressure airconduits and which also supports the sealing means cannot, in manyinstances be suitably placed on a face surface of the rotating cylinder,namely in the case where the face surface of the rotating cylinderimmediately abuts against another construction element and is thereforeinaccessible. Moreover, the production of pressure fluid conduitsbetween the cylindrical members has hitherto been very difficult.

In another known embodiment of the device for. feeding pressure fluid ofthe aforementioned type, a ring provided with pressure fluid conduits isarranged on the outer cylinderical surface of the rotating member and isguided thereon whereby separate sealing means are assigned to eachpressure fluid outlet and are disposed in a ringshaped recess of. therotating cylinder and/or of the stationary ring. The sealing means areprovided with sealing lips for guiding the pressure fluid therebetween.The outer diameter of the sealing lips is elastically deformable. Inpractice, this prior art embodiment has given very satisfactory resultsin connection with pressure air, but it is unusable for feeding pressureair from a stationary member into a rotary construction element.

Accordingly, the principal object of this invention is to avoid theaforementioned disadvantages of prior art devices of this kind.

In particular, an object of this invention is to provide a contactlessconnection between a stationary member and a rotating member andmaintain a flawless sealing against the leaking of the pressure fluid.

Another object of this invention is to provide a device for feedingpressure fluids from a stationary pressure source into a rotatingmember, which has a minimum mounting space and an excellent operationalreliability.

Still another object of this invention is to provide a pressure fluidfeeding device of the above type which can be easily produced by simpleproduction means.

SUMMARY OF THE INVENTION According to this invention the aboveobjects'are attained by providing the outer circumferential portion ofthe rotating cylinder of the chuck body with an annular recess, andinserting a non-rotatable ring into the recess in such a manner that acertain backlash or play in the axial direction is maintained betweenthe end surfaces of the ring and the annular recessed walls of saidrotatable cylinder or chuck defining thus two opposite interspaces. Thefacing annular walls of the nonrotatable ring and of the radiallyrecessed portion of the chuck or cylinder are shaped so as to form anaxially recessed annular region, and flat annular surfaces acting aspressure throttling zones adjacent the recessed annular regions. Thepressure fluid conduit from the non-rotatable ring opens into onerecessed region and transmits the pressure fluid into a correspondingpressure fluid conduit portion disposed within the rotating part. Thepressure transmitting regions in opposite interspaces are mutuallyconnected through a passage and due to the axial play of thenon-rotatable ring and due to the pressure throttling effect of thethrottling zones the non-rotatable member starts vibrating in axialdirection and thereby continuously adjusts the pressure balance'betweenthe respective interspaces when the pressure fluid is applied in one ofthe pressure transmitting regions.

In a preferred embodiment of this invention, the rotating cylinder orthe chuck body is assembled from two parts which are firmly connectedone to another and which are shaped in such a manner as to produce onthe cylindrical surface of the rotating body an annular recess forreceiving the non-rotatable ring and for defining its axial movement.The non-rotatable ring contains the pressure fluid conduits connected toa pressure source outside the device.

It is of course also possible to produce the rotating body as a singlepiece wherein the recess is machined on its periphery and thenon-rotating ring is assembled of several mutually firmly connectedpieces.

As it has been mentioned above, on each end surface of the non-rotatablering are provided axially recessed pressure transmitting areas arrangedbetween the pressure throttling zones; the pressure transmitting areasin respective interspaces are interconnected and the pressure fluidfeeding conduit opens into one of the pressure transmitting areas. Theinterconnection of the respective pressure transmitting areas can becarried out either by a separate channel or through the pressure fluidfeeding conduit which directly opens into one of the pressuretransmitting regions and is connected with the other pressuretransmitting area through a constant throttle valve in the form of astop aperature, for instance. It will be noted that the facing planesurfaces in the throttling zone act as variable throttles.

The aforementioned two-piece assembly of the rotating cylinder has theadvantage that it makes it possible to adjust arbitrarily the width ofthe recessed portion by inserting a spacing ring between the two partsbefore the final assembly of the rotating member.

It is also advantageous to create leakage fluid collecting chambers inthe throttling zones. These collecting chambers are made preferably inthe non-rotatable ring and have the form of annular recesses. Inaddition, the opposite sidewall portions of the non-rotatable ring whichproject above the cylindrical surface of the rotating body are equippedwith sealing collars abutting against the rotating surface andprotecting thus the interspaces against the penetration of coolingliquid for example.

Referring again to the connecting channel between opposite pressuretransmitting regions, it is also possible to design the non-rotatablering for backlash or play in radial direction so that no provision foradditional interconnecting passages is necessary.

In the modification of the interconnection which employs constantthrottle valves, it is advantageous to provide either the bottom of theannular recess, the rotating member or the inner cylindrical surface ofthe nonrotatable ring with an abrasion resistant coating such as forinstance of molybdenum or abrasion resistant plastics, or if no constantthrottle valve is employed, the interconnecting passage can be made inthis abrasion resistant layer.

In using the device of this invention in connection with a hydraulicallycontrolled chuck body, there are provided pressure fluid conduitportions for feeding as well as for return of the pressure fluid and amultiple switching valve is ,operatively connected between the twoconduit portions to selectively control the direction of the pressurefluid.

In order to secure the non-rotatable ring against an gular displacementbut at the same time allow an axial movement thereof, the ring isprovided with a projecting pin which engages a bifurcated member. Thering is made preferably of a self-lubricating material such as forexample a sintered body soaked with oil.

To further improve the protection of lateral interspaces in the recessagainst leakage of pressure fluid, there are provided sealing surfaceslocated preferably in the area between the circumference of thenonrotatable ring and the leakage fluid collecting chambers and forsealing rings disposed in annular grooves in the sealing areas of thenon-rotatable ring.

This invention makes it possible that the structure of the device forfeeding pressure fluid from a nonrotatable part into a rotating part canbe considerably simplified and, above all the operational reliability ofthe device is considerably increased. The extremely high reliability ofoperation results due to the fact that when the pressure fluid isapplied through the feeding conduit into a recessed pressuretransmitting portion between the facing end surfaces of the rotatingmember and of the non-rotatable ring, the pressure fluid when applied torespective throttling zones and pressure transmitting regions inopposite interspaces, causes continuous vibrations of the non-rotatablering in its axial direction and thereby a self-adjustment of thepressure balance between the respective interspaces. In this mannerthere results a contactless connection between the metal surfaces of therotating and the nonrotatable parts whereby the sealing effecttherebetween is fully maintained.

The production costs of the device of this invention is very low, sincethe rotatable ring can be manufactured in a very simple manner forexample by forming a sintered ferrous material; in addition, thearrangement of the ring in the annular recess of the rotating bodyrequires minimum installation space. Consequently, the size of theassembled rotating part practically does not increase.

Because of the hydrostatic pressure balance attained by the axialvibrations of the non-rotatable ring, the coupling between the rotatingpart and non-rotating part is frictionless and nowhere abrasion can takeplace.

From the aforementioned brief outline of the arrangement and ofadvantages of the device of this invention it is apparent that thedevice in spite of its very simple design insures a high operationalreliability.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of thisinvention, reference is had to the following description of severalembodiments of a device for feeding pressure fluid from a non-rotatablepart into a rotating part according to the invention, taken inconjunction with the Figures in the accompanying drawing, in which:

FIG. 1 is a fragmentary elevational view partly in section of a heavyduty chuck which is provided with one embodiment of a pressure fluidfeeding device of this invention;

FIG. 2 is a sectional elevational view of another modification of thepressure fluid feeding device of this invention;

FIG. 3 is a side view, partly in section of a mounting support of thenon-rotatable ring shown in connection with the chuck of FIG. 1; and

FIG. 4 is a side view, partly in section of another modification of themounting support of FIG. 3.

DETAILED DESCRIPTION Referring now to FIG, 1, there is shown a rotatableheavy duty chuck designated by reference numeral 1 which is formed bycylindrical chuck body 2 and by clamping jaws 5 arranged for radialmovement on one end face of the chuck body 2. For controlling the radialmovement of the clamping jaws 5, there is provided within the chuck body2 a pressure device including a hydraulic cylinder 9 and an axiallymovable piston 6 connected with an intermediate piece 7. The clampingjaws 5 are arranged in a conventional manner for clamping a workingpiece (not shown) which is to be machined.

To supply pressure fluid into the pressure cylinder 9 which rotatestogether with the chuck 1, the chuck body 2 is provided on itscircumferential portion with an annular recess 16 into which anon-rotatable ring 17 is inserted with a certain axial backlash or play.The pressure fluid is supplied from a stationary hydraulic aggregate 12through pressure fluid conduits 13, 14 into a multiple switching valve30 and therefrom into conduit portions 28 and 29 provided within thenonrotatable ring 17 to communicate with corresponding pressure conduitportions 44 or 45 in the rotating part, as it will be explained later.

The chuck body 2 is made of two mutually fixedly connected parts 3 and 4which when assembled form on the outer cylindrical surface portion 38 ofthe body 2 an annular recess 16 which is formed for receiving thenon-rotatable ring 17. In addition, the interior of the chuck body 2includes the pressure cylinder 9 in which an axially movable pressurepiston 6 is acted upon by the pressure fluid from the feeding conduit 13and is moved to the left; the other end surface of piston 6 is providedwith a pressure space into which the pressure fluid is applied throughthe pressure conduit portion 45 when the pressure conduit 13 is closed,thereby moving the piston to the right.

The movable piston 6 is connected with an intermediate movable piece 7which is provided at its free end with inclined surfaces mating withcorrespondingly inclined surfaces 8 on respective clamping jaws 5. Inthis manner, the axial movement of the hydraulically controlled piston 6is transformed into the radial movement of clamping jaws 5.

As it has been mentioned above, the non-rotatable ring 17 is providedwith two conduit portions 28 and 29 which are alternatively suppliedwith pressure fluid from the hydraulic aggregate 12. In the embodimentshown in FIG. 1, the two conduit portions 28 and 29 are arranged in aspaced relation one to another and open at the same end surface of thering 17.

To adjust the axial backlash or play of the ring 17 within the annularrecess 16, a spacing ring 11 is inserted between the two parts 3 and 4of the chuck body 2. By replacing the spacing ring 11 for another onehaving a different thickness, it is possible to adjust the interspacesresulting between the recessed walls of the rotating cylinder 2 and theend surfaces 39 and 40 of the non-rotatable ring 17.

According to one feature of this invention, the orifices of respectivepressure fluid conduit portions 28 and 29 within the non-rotatable ring17 open into an annular recessed region facing the orifices ofcorresponding conduit portions 44 and 45 within the rotating chuck body2. These annular recesses form thus pressure transmitting regions 41whereby the remaining surface in the interspace form pressure throttlingzones 18. On the other end surface of the ring 17 there is also provideda similar pressure transmitting region 42 having however an increasedsurface with respect to the regions 41 on the opposite end surface; thepressure transmitting region 42 borders with a pressure throttlingsurface 19 formed between the wall 40 of the ring 17 and the recessedsurface of the part 3. The pressure transitting surface 42 is connectedwith the throttling zone 18 at the opposite face of the ring 17 throughan axially directed passage 20. Due to this arrangement, when thepressure fluid is applied into the pressure transmitting region 41, theresulting pressure axially displaces the ring 17 to the left and keepsclosing the variable throttle 19. During this displacement, however, theother variable throttle 18 opens the axial passage 20 and the pressuregrowing in the pressure transmitting region 42 displaces the ring 17 tothe right, thereby closing the gap between the throttling surfaces 18which action, in turn, results in an increased pressure in the pressuretransmitting region 41, etc. Due to this respecting action, therotatable ring 17 vibrates to and fro in opposite axial directions,thereby maintaining the pressure balance between the two oppositeinterspaces.

According to another feature of this invention, annular pressure fluidcollecting chambers 24 and-25 are provided in the sealing surfaces 39and 40 of the nonrotatin'g ring 17 and are connected through a leakageor return conduit 15 to the hydraulic aggregate 12.

Still another feature of this invention is the provision for collars 23and 24 which are connected with a circumferential portion of thenon-rotating ring 17 and seal the interspaces for example against thepenetration of a cooling liquid, if any. The sealing collars 23 and 24have preferably an angular configuration to provide for annular chambers25 and 26 wherein a splash ring 43 may be located.

Referring now to FIGS. 3 and 4 there are illustrated by way of anexample two modifications of the mounting arrangement of thenon-rotatable ring 17 of this invention. To insure that the ring bestationary into the direction of rotation of the chuck body but that itbe' movable in axial direction, a pin 36 or a bolt 32 projects from thering 17. The bolt 32 is guided in axial direction within the slot of afixedly mounted slotted piece 31 (FIG. 3) or gable 37 (FIG. 4). In themodification as shown in FIG. 3, the annular passage 20 connecting thepressure transmitting regions 41 and 42 and resulting due to the radialplay of the ring 17 (as shown in FIG.- 1), can be radially adjusted bynuts 33 which are threaded on the bolt 32 and hold the ring 17 at apredetermined radial position, thereby. fixing the clearance of the slotor passage 20.

In the modification as shown in FIG. 4, pin 36 is guided between theprongs, of the gable or fork 37 and the cylindrical bottom portion ofthe recess 16 in the rotating part is covered by an abrasion resistantcover layer 34 made, for example of molybdenum or plastic. For theinterconnection of respective transmitting regions 41 and 42 there isprovided within the abrasion resistant cover layer 34 a separate channel35 through which the pressure fluid keeps the pressure balance in therespective interspaces Referring again to FIG. 1, the operation of thepressure feeding device of this invention is as follows:

When pressure fluid from the hydraulic device 12 is applied throughpressure conduit 13, switching valve 30 and the pressure conduit portion28 passing through the non-rotatable ring 17 and entering into thepressure transmitting region 41, it continues flowing through thepressure fluid conduit portion 44 and the reversing valve 27 into thepressure space of the hydraulic cylinder 9 at the right hand end of thepiston 6. The applied pressure moves the piston 6 to the left as far asto the end position as indicated in FIG. 1. The intermediate piece 7 ishereby moved also to the left and the clamping jaws 5 are radiallydisplaced to the center to clamp a workpiece (not shown). When thereversing valve 27 is switched over, the pressure fluid from the conduitportion 44 is fed through the conduit portion 45 into the pressure space10 at the left hand end surface of the piston 6 and the piston 6 movestothe right whereby the radial movement of clamping jaws 5 is reversed.

In spite of the fact that no sealing means are provided between thechuck body 2 and the non-rotating ring 17 within the recess 16, thereresults a hydrodynamic sealing effect between the facing end surfaces ofthe chuck body and of the ring 17. Upon admission of the pressure fluidinto the pressure transmitting region 41 the ring 17 is moved to theleft so that the throttling zone 19 is almost closed. In this position,a minute amount of the pressure fluid enters the collecting chamber 21;nevertheless since the throttling zone 18 is open, the pressure fluidacts also in the pressure transmitting region 42 and keeps moving thepiston 6 to the right so long until the pressure acting upon thetransmitting region 42 is in balance with the pressure acting in thepressure transmitting region 41. The pressure region 42 which is locatedopposite to the pressure region 41 into which the pressure fluidconduits are opening,have preferably a larger area than that of theregion 41.

Due to this self-adjusting pressure relief and pressure increase, thering 17 maintains automatically continuous vibrations whereby throughthe alternating variations of the throttling zones 18 and 19 thepressure fluid is more or less throttled and consequently the pressureforces are kept in dynamic balance. For this reason, no contact of theend walls of the ring 17 with the end walls of the recessed end wallportions 29 and 40 of the chuck body 2 takes place and accordingly nometallic friction occurs. Moreover, the continuously alternatingpressure increases and pressure decreases guarantee minimum axialdisplacement of the ring 17. Should the facing end walls in aninterspace abut against each other, the pressure in the assignedpressure transmitting region would increase to such a degree that thering 17 would become instantaneously disengaged from such a contact. Itis evident that in this manner the flawless sealing action between therotating chuck body 2 and the non-rotatable ring 17 is fully insured.The throttling zone 18 located between the return conduit portion 29 andthe leakage fluid collecting chamber 21 cooperates with leakage fluidcollecting chamber 21 which is located in the remaining peripheralsurface portion 39 of the ring 17. Due to the effect of the so-calledthermical wedge which results in sealing the interspaces between the endsurfaces of the ring 17 and the end surfaces of the recessed chuck bodyportion, further leakage of the pressure fluid in outward direction iseffectively prevented.

In order to release the clamping pressure of the jaws against theworkpiece during the standstill of the chuck 1, the multiple switchingvalve 30 which is located outside the rotating parts, makesit possibleto change the direction of flow of the pressure fluid from the conduitportion 28 to the conduit portion 29 and vice versa. When pressure fluidis applied to the conduit portion 29, the non-rotatable ring 17 isdisplaced to the left in the same manner as it has been described abovewith reference to the pressure conduit 28. The throttling zone 19 almostcloses the left hand interspace when the pressure fluid flows boththrough the conduit portion 45 into the pressure space and through theaxial passage into the pressure transmitting region 42. The leakingfluid is again collected in collecting chambers 22 and 21 and returnedto the hydraulic aggregate 12. Thus, in general, as more pressure fluidis fed into the hydraulically controlled chuck 1 than can leak throughthe throttling surface 18', the leakage fluid loss, even during thestandstill of the nonrotatable part, is significant.

In the embodiment of the pressure fluid feeding device of thisinvention, as illustrated in FIG. 2, the cylinder 51 is assembled ofthree firmly connected parts 52, 53 and 54, which form again an annularrecess 55 for receiving ring 56 which is provided with pressure fluidconduit portions 57 and 58 as well as with pressure fluid collectingchambers 66 and 67 and leakage fluid return conduit portion 59.Similarly as in the previously described embodiment of FIG. 1, there areprovided pressure transmitting regions 62 and 63 having differentsurface areas. The pressure transmtting region is provided on the endsurface 65 of the ring 56 whereas the pressure region 63 is defined by arecess provided in a recessed wall of the part 53. In this particularembodiment, no separate inter-connecting channel or passage is providedbetween respective pressure transmitting regions. Instead, the pressurefluid conduit 57 which opens into the region 62 is provided with abranch conduit 57 which opens through a constant throttle 61 into thepressure region 63. The interspace area 60 adjacent the pressure region63 acts thereby as a variable pressure throttling zone. In additionthere are provided in the ring 56 leakage oil collecting chambers 66 and67 as well as a groove 68 for receiving the sealing ring 69.

The operation of the embodiment of FIG. 2 is as follows:

As soon as the pressure fluid is applied through the feed conduit 57 tothe pressure region 62 and further forwarded throughchannels 72 in therotating cylindrical part 52, the high pressure of the pressure fluid inthe region 62 axially displaces the ring 56 to the right and thepressure throttling zone 60 continues closing. Through the conduitbranch 57' and the constant throttle 61 the pressure fluid is suppliedinto the pressure region 63 which is larger than the pressure region 62.In spite of the fact that due to the effect of the fixed throttle 61only a reduced amount of the pressure liquid is delivered into theregion 63, the pressure in this region 63 increases proportionally tothe closing of the throttle zone 60. Because of the larger area of thepressure region 63 in comparison with region 62, the ring will move tothe left so far until a pressure balance is established between the twopressure regions. In this manner a contact of the ring 56 against theparts 52 and 53 is reliably avoided. The pressure relief conduit 58 isprovided in the ring 56 and opens into an annular recess opposite topressure relief portion 73 in the rotating part 53.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

Having thus described the invention what I claim as new and desire to besecured by Letters Patent is as fol lows:

1. A device for feeding a pressure fluid from a stationary pressuresource into a rotatable member including a pressure fluid actuateddevice controlled by said pressure fluid, comprising,

an annular recess defining opposite radial end surfaces and an endlessbottom wall in a circumferential portion of said rotatable member andbeing concentric with the axis of rotation thereof,

a single non-rotatable annular member disposed within said recessdefining opposite radial faces each facing an end surface, and having anaxial play producing opposite interspaces one between each face and theend surface of said members, said end faces in each interspace having apressure transmitting annular recessed region and a pressure throttlingzone formed by a face portion surrounding said region,-

a first pressure fluid conduit portion connected to said source anddisposed within said non-rotatable annular member and opening into oneregion,

a second pressure fluid conduit portion connected to said pressure fluidactuated device and disposed in said rotatable member and opening intosaid one region near said first conduit portion,

said one region being interconnected by passage means with the oppositeregion, one of said regions having a larger area than the other region,whereby said zones produce a self-adjustable pressure balance betweensaid interspaces by axially reciprocating said non-rotatable member whensaid pressure fluid is fed through said first conduit portion into saidone pressure fluid transmitting region.

2. A device according to claim 1, wherein said rotatable member is achuck body with radially movable jaws and said pressure fluid actuateddevice is a hydraulic piston axially movable in said rotatable memberand operable for controlling the jaws of said chuck body.

3. A device according to claim 1, further comprising annular chambersdefined in said non-rotatable member and respectively opening into saidzones for collecting leakage fluid emanating from said regions.

4. A device according to claim 3, further comprising sealing meanslocated in at least one of said interspaces between the circumference ofsaid rotatable member and said leakage fluid collecting chambers.

5. A device according to claim 1 wherein said first conduit portionincludes a branch connected to said opposite region and comprising aconstant throttle, whereby said zones operate as variable throttles.

6. A device according to claim 1 wherein said nonrotatable annularmember is made of a selflubricating material.

7. A device according to claim 2 further including additional conduitportions for selectively controlling the movement of said hydraulicpiston, and additional pressure transmitting regions and pressurethrottling zones assigned to said additional conduit portions.v

8. A device according to claim 2 wherein said chuck body is assembled oftwo parts defining said annular recess and said hydraulic cylinder, saidtwo parts being connected to each other through exchangeable spacermeans designed for adjusting the axial play of said nonrotatable member.

9. A device according to claim 2, further comprising means for holdingsaid annular member in a nonrotatable position and for allowing axialdisplacement of said annular member.

10. A device according to claim 2 wherein said nonrotatable annularmember has a larger diameter than said recess thereby extending beyondthe confines of said rotatable member, at least one of the extending endwall portions of said non-rotatable member being provided with a sealingcollar abutting against said chuck body for sealing the interspacesagainst the entry of any cooling liquid.

11. A device according to claim 3 further comprising a reversing valveassociated with said second conduit portions in said rotatable memberfor controlling the flow of said pressure fluid into said pressuredevice.

12. A device according to claim 1 wherein said nonrotatable member has aplay in radial direction as against said rotatable member defining saidpassage means between its cylindrical wall and the cylindrical bottom ofsaid recess.

13. A device according to claim 12 wherein the bottom wall of saidrecess is provided with an abrasionresistant cover layer.

1. A device for feeding a pressure fluid from a stationary pressure source into a rotatable member including a pressure fluid actuated device controlled by said pressure fluid, comprising, an annular recess defining opposite radial end surfaces and an endless bottom wall in a circumferential portion of said rotatable member and being concentric with the axis of rotation thereof, a single non-rotatable annular member disposed within said recess defining opposite radial faces each facing an end surface, and having an axial play producing opposite interspaces one between each face and the end surface of said members, said end faces in each interspace having a pressure transmitting annular recessed region and a pressure throttling zone formed by a face portion surrounding said region, a first pressure fluid conduit portion connected to said source and disposed within said non-rotatable annular member and opening into one region, a second pressure fluid conduit portion connected to said pressure fluid actuated device and disposed in said rotatable member and opening into said one region near said first conduit portion, said one region being interconnected by passage means with the opposite region, one of said regions having a larger area than the other region, whereby said zones produce a self-adjustable pressure balance between said interspaces by axially reciprocating said non-rotatable member when said pressure fluid is fed through said first conduit portion into said one pressure fluid transmitting region.
 2. A device according to claim 1, wherein said rotatable member is a chuck body with radially movable jaws and said pressure fluid actuated device is a hydraulic piston axially movable in said rotatable member and operable for controlling the jaws of said chuck body.
 3. A device according to claim 1, further comprising annular chambers defined in said non-rotatable member and respectively opening into said zones for collecting leakage fluid emanating from said regions.
 4. A device according to claim 3, further comprising sealing means located in at least one of said interspaces between the circumference of said rotatable member and said leakage fluid collecting chambers.
 5. A device according to claim 1 wherein said first conduit portion includes a branch connected to said opposite region and comprising a constant throttle, whereby said zones operate as variable throttles.
 6. A device according to claim 1 wherein said non-rotatable annular member is made of a selflubricating material.
 7. A device according to claim 2 further including additional conduit portions for selectively controlling the movement of said hydraulic piston, and additional pressure transmitting regions and pressure throttling zones assigned to said additional conduit portions.
 8. A device according to claim 2 wherein said chuck body is assembled of two parts defining said annular recess and said hydraulic cylinder, said two parts being connected to each other through exchangeable spacer means designed for adjusting the axial play of said non-rotatable member.
 9. A device according to claim 2, further comprising means for holding said annular member in a non-rotatable position and for allowing axial displacement of said annular member.
 10. A device according to claim 2 wherein said non-rotatable annular member has a larger diameter than said recess thereby extending beyond the confines of said rotatable member, at least one of the extending end wall portions of said non-rotatable member being provided with a sealing collar abutting against said chuck body for sealing the interspaces against the entry of any cooling liquid.
 11. A device according to claim 3 further comprising a reversing valve associated with said second conduit portions in said rotatable member for controlling the fLow of said pressure fluid into said pressure device.
 12. A device according to claim 1 wherein said non-rotatable member has a play in radial direction as against said rotatable member defining said passage means between its cylindrical wall and the cylindrical bottom of said recess.
 13. A device according to claim 12 wherein the bottom wall of said recess is provided with an abrasion-resistant cover layer. 